Powder distributing apparatus



Dec. 1, 1942. M. H. HERMANN ErAL l POWDER DISTRIBUTING APPARTUS Filed Dec. 25, 1940 Patented Dec. 1, 1942 e UNTTED STATES PATENT OFFICE rownna nrsramum ArrAaA'rUs Milton H. Hermann and Sollie Hergott,

A Chicago, lll.

Application December 2s, 194e, serial No. 311,296

9 claims. (ci. 91.-45) j This invention has to do with apparatus employing an air streanrfor turbulating and thus taking powder particles into suspension for conveying such particles to a distributing area, and relates more particularly to an air inlet tube in association with a powder container and means for adjusting the relative position of the powder body from which the particles are taken and the tube whereby the concentration of suspended particles may be accurately regulated.

Apparatus of the present character is used extensively in the printing and lithographing iields where the powder is sprayed onto the freshly inked faces of sheets as they leave the presses, prior to stacking. The eilect of this powder is to prevent offset of ink from any sheet onto the back of the sheet stacked thereagainst. While it is necessary that suiiicient powder shall be deposited upon the sheets to prevent oilset," it is also highly desirable that there shall be no deposits in excess of this amount. First because too much powder which is easily detected by 4the fingers has for some persons an unpleasant feel or touch, and secondly because a portion of the excess drifts away in the atmosphere where it is inhaled by the pressman.

stream circumferentially about the side walls of a powder container above the surface of a powder body therein.

These and other desirable objects inherent in A and encompassed by the invention will later appear.

In the drawing:

Fig. 1 is a perspective view of a powder distributing apparatus constructed according to the principles of the present invention;

Fig. 2. is a fragmentary sectional View taken upon a plane coinciding with the principal axis an open top which is closed by a screwed-on cap One object of the present invention is the provision of a powder distributing apparatus capable of wide and accurate variation in the amount of powder suspended-in an air or gas 4stream passing therethrough. A

Another object of the present invention is the provision of an apparatus as the above in which the powder concentration can be modified independently of the streams velocity. This is accomplished by adjusting the distance between the mouth of an air inlet tube and the surface of a loose powder body whereby the intensity with which the air streamv encounters said surface and the consequent amount of powder particles picked up thereby may bel selectively regulated.

The inventionhas for another of its objects the provision in a powder spraying apparatus, wherein powder particles are picked up from a loose powder body by an air stream, of one or more light-weight Apellets or balls agitatable by such air stream to break down surface irregularities in the powder body and thusprevent the formation of any substantial crater by erosion. Greater uniformity in the quantity of powder carried by the air stream is thereby assured.

A further object of the invention is the pro'vision of an improved air inlet tube having its discharge end disposed for directing an air II'. Preferably the container side wall lI2 is made of transparent material such as glass so the height of a powder body I3 therein can be vconveniently ascertained by observation. During der body I3 picks up particles therefrom and I conducts them away to a desired place for deposit. The air, which term is herein used to include any gas, is introduced through a. tube I4 which has a vertical section I5 and a substantially horizontal section I6 disposed adjacently to the wall I2 and curved to conform with the curvature thereof. A discharge opening II is at the end of said curved section.

In Fig. 2 the Vertical part I5 of the tube I4 will be seen to extend upwardly through an opening ila in the cap II into a cylindrical casing C.` This casing C is connected by means of screw threads I8 with a threaded plug I 9 which in turn is in threaded engagement with the opening IIa. Said plug I9 is provided with an axial opening 20 through which vthe vertical portion I5 of the tube I4 projects.

The upper end of the tube section I5 has an enlarged circumferential section 2| which is bevelled about `its upper side for seating against a shoulder 22 circumscribing an axial bore 23 within a piston or plunger 24 which is reciprocal vertically within the cylindrical casing' C- A .the enlarged portion 2| of the tube snugly against the shoulder 22 and thus holding the tube I4 in rigid assembly with the plunger 24.

One side of the plunger 24 has a slot 21 extending lengthwise thereof and forming cornplementally with the cylindrical casing I1 an air intake chamber. Said slot 21 registers with a threaded side wall opening 28 of the casing I1 wherein there is turned a nipple 29 having an end section 30 which projects into the slot 21 to prevent rotation of the plunger 24 while permitting of axial adjustment thereof. One end of an air intake conduitl 3| is connected with the nipple 29, the opposite end of said conduit being communicable with a source of air under pressure.

hence of the tube I4 connected therewith is had by means of a threaded stem 32 in combination with a knurled nut 33 which is held againstaxial displacement by a bracket 34 of which a base the direction of rotation of said nut.

In the operation of the apparatus, a valve (not shown) between the conduit 3| and a source of air under pressure will be opened to cause the flow of such air through the conduit 3I and thelnipple 23 into the intake chamber formed by the slot 21. There is a sumciently close fit between the plunger 24 and the casing C to prevent the escape of air past either end of the plunger so that the air flows downwardly through the bore 23 and the tube` I4 into the container Il! from the discharge end I1 of said tube. Due to the position of the tube I4 the discharged air will be caused to whirl about the container wall I2, and to expedite the air movement the wall I2 is preferably cylindrical, or nearly so. While passing over the exposed surface of the powder body I3 the air stream will pick up powder particles so that a dust cloud will be formed above the powder body and discharged from the container through an opening I I b in the cap II, a conduit 43 of which .an end is in threaded relation with said opening IIb, a multi-duct coupling member 44 and one or more conduits as 45 and 46 to spray heads 41 or the like. The spray head 41 shown in Fig. 1 has a transverse slot 48 through which the powder laden. air is discharged.

The amount of powder suspended in a unit quantity of air can be accurately regulated .by changing the elevation of the tube I4 and thus varying the proximity of the swiiter part of the air current leaving the tube I4 and the powder surface. When it is desired to increase the quantity of powder particles per unit quantity of air, the tube I4 will be lowered by rotating the knurled nut I3 counterclockwise as viewed from above and when it is desired to decrease the amount of powder per unit quantity of air the nut 33 will be rotated in the opposite direction until said tube is raised to the required position. Sometimes it will be desirable to change the velocity of the air stream so the particles will be shot a different selected distance from the spray heads but without changing the amount of pow- Vertical adjustment of the plunger 24 and der per unit volume of air. This adjustment can 75 be made by changing the degree of opening of the valve (not shown) between the air source and the conduit 3| until the air issuing from the spray heads is at the desired velocity and then placing the tube I4 at the elevation necessary to obtain the required pick-up of powder particles.

The absence of surface irregularities and of crater-like formations within the upper surface of the powder body is assured by one or more light balls or pellets 49, two being shown in Figl, which are vturbulated and carried about by the air stream. Hollow thin-shelled spherical balls when used for this purpose have been found to keep the surface of the powdered body comparatively smooth and uniform in contour so that the amount of powder picked up by the air stream, will not fluctuate once the aforesaid valve (not shown) has been selectively set. There will be a gradual-diminution in the powder content of the air stream as the surface of the powder body recedes pursuant to erosion by the air stream, but since the erosion process is very slow the desired amount of powder discharged can be regulated suiiiciently close for practical use and purposes by periodically rotating the nut 33 to cause re-adjustment of the stem I4.

A safety valve 5I! of any standard structure attached to the cap II prevents excessive air pressure in the container.

In a modified form of the invention shown in Fig. 3 a container 60 holding a body 6I of powder is provided with a cap 62 from which there depends an air inlet' tube 63 of which the lower end is shaped similarly to the tube I4. Air is introduced into the device through a conduit 64 which communicates with the upper end of said tube 63. Discharge of the dust cloud formed by the air stream and powder picked up from the body 6| is discharged through an opening 65 in the cap "62 and a conduit 66 which corresponds to the conduit 43.

Relative vertical adjustment between the tube 63 and the upper surface of the powder body 6i is taken care of by means of a piston or axially movable bottom member 81 in the lower p art of the container. This bottom member 61 has a threaded stem 68 projecting downwardly therefrom through openings 69 and 10 in a bracket 1I which is integral with a spider 12. A flange 13 upon the spider 12 abuts against the upper side of an inwardly projecting flange 14 upon the bottom. of the container side wall, and a threaded ring 15 turned upon a threaded exterior section of the spider 12 cooperates with the flanges 13 and 14 for holding this spider in position upon the container. A knurled nut 16 disposed between the legs of the bracket 1I is in threaded relation with the stem 68 and can' be rotated for effecting vertical adjustment of said stem and the bottom member 61 to raise or lower the powder body and thus regulatethe spacing of said body and the tube 63 for the purpose explained with respect to the tube I4.

While we have herein shown and described but two speciflc embodiments, it should be understood that the invention .extends to other arrangements, details and structures falling within the spirit thereof.

We claim:

1. Powder` distributing apparatus comprising a closed container adapted to hold a body of such powder, tube support means, an air inlet tube upon said support means and projecting into the container, said tube including discharge opening means for normal operation only above the surface of said powder body and in the form of a discharge opening disposed adiacently to and facing horizontally in general parallelism with the adjacent portion of a side wall of the container to direct the discharge of air carried into the container thereby horizontally along said wall at a section above the powder body whereby the discharged air creates in said container a circular current laden with powder picked up solely from the surface of said body, and said container having an opening above the powder body for the discharge of the powder laden air.

2. Powder distributing apparatus comprising a closed container adapted to hold a body of such powder, a channelled air inlet member disposed in said container, the channel in said member having an air outlet portion normally above the powder body and disposed for directing the discharge of air therefrom into the container horizontally along a wall section of said container, means for effecting relative movement between said powder body and said member to selectively change the relative position of the powder body and the air stream, and said container also having a discharge opening normally above such powder body.

3. Powder distributing apparatus comprising a closed container adapted to hold a body of such powder, a channelled air inlet member in the container with the outlet portion of the channel therein normally disposed above. said powder body, and said outlet portion of the channel being constructed and arranged to direct the discharge of air carried thereby into the container horizontally along a wall section of the container, means for adjusting said channelled member vertically to selectively vary the distance between said member and the `surface of said powder body, and said container also having a discharge opening above such powder body.

4. Powder distributing apparatus comprising a y closed container adapted to hold a body of such ciprocally mounted in said cylinder, said tubebeing connected with said plunger for movement therewith, said plunger setting off above at least a part thereof an interior portion of said cylinder as an air receiving chamber, said cylinder having an air inlet opening communicating with said chamber, and said plunger having a passage communicating between said chamber and said tube.

5. Powder distributing apparatus comprising a closed container adapted to hold a body of such powder, an air inlet tube having a discharge section in said container, said container having an outlet opening above the normal level of such a powder body, and means for adjusting the elevation of said tube comprising guide means, a

coupling head adjustable generally vertically in said guide means and having an air inlet passage therein and manually operable means for adjusting said head in said guide member, and said tube being connected with said coupling head for movement therewith and also being connected communicatively with said air inlet passage therein.

6. Powder distributing apparatus comprising a closed container having a generally cylindrical upright side wall and adapted to hold a body of such powder, said container also having an outlet opening above the normal level of such a powder body, an air inlet tube including a substantially horizontal'discharge end portion disposed adjacently to and generally in parallelism with a section of said side wall and an upwardly extending portion, and means for adjusting the elevation of said tube comprising upright guide means, a member adjustable generally vertically in said guide means, and manually operable means for adjusting said head in said guide means, and said upwardly extending portion of the tube being connected with said head for movement therewith.

'7. Powder distributing apparatus comprising a closed container having a generally vertical side wall closed upon itself for circumscribing a body of such powder and for deecting an air stream circularly about the inner periphery of such wall, said container also having an outlet opening for such air above the section of the container for occupation by a powder body, an air inlet conduit including a discharge section in the container entirely above the normal level of a body of such powder and in the form of an opening disposed adjacently to a portion of said wall and facing horizontally in general parallelism withv said wall portion, powder body supporting means adjustable vertically in said container, and manually operable means for adjusting said supporting means.

8. Powder distributing apparatus comprising a closed container adapted to hold a body of powder, air' injection means disposed for directing a stream of air over the surface of said powder body for picking up powder particles, means for conducting the particle laden air stream from said container, and at least one pellet member in said container in the path of such air stream and sufficiently light in weight to be propelled thereby over the surface of said body during operation of the apparatus.

9. Powder distributing apparatus comprising a closed container adapted to hold a body of such powder, tube support means, an air inlet tube in said container and held by said support means, said tube having a. discharge opening facing generally horizontally in one direction along a wall section of the container at a position normally above the level of a powder body therein, means for adjusting said tube vertically to vary the distance between said opening and the surface of said powder body, and said container also having a discharge opening above the space therein'for said powder body. 

